Configurations Using Udp Helper; Udp Helper With Broadcast-All Addresses - Dell Force10 Z9000 Configuration Manual

Figure 20-12. Configuring a Broadcast Address
FTOS(conf-if-vl-100)#ip udp-broadcast-address 1.1.255.255
FTOS(conf-if-vl-100)#show config
!
interface Vlan 100
ip address 1.1.0.1/24
ip udp-broadcast-address 1.1.255.255
untagged GigabitEthernet 1/2
no shutdown
View the configured broadcast address for an interface using the command
Figure 20-13.
Figure 20-13. Configuring a Broadcast Address
R1_E600(conf)#do show interfaces vlan 100
Vlan 100 is up, line protocol is down
Address is 00:01:e8:0d:b9:7a, Current address is 00:01:e8:0d:b9:7a
Interface index is 1107787876
Internet address is 1.1.0.1/24
IP UDP-Broadcast address is 1.1.255.255
MTU 1554 bytes, IP MTU 1500 bytes
LineSpeed auto
ARP type: ARPA, ARP Timeout 04:00:00
Last clearing of "show interface" counters 00:07:44
Queueing strategy: fifo
Input Statistics:
0 packets, 0 bytes
Time since last interface status change: 00:07:44

Configurations Using UDP Helper

When UDP helper is enabled and the destination IP address of an incoming packet is a broadcast address,
FTOS suppresses the destination address of the packet. The following sections describe various
configurations that employ UDP helper to direct broadcasts.
• UDP Helper with Broadcast-all Addresses on page 436
• UDP Helper with Subnet Broadcast Addresses on page 437
• UDP Helper with Configured Broadcast Addresses on page 438
• UDP Helper with No Configured Broadcast Addresses on page 438

UDP Helper with Broadcast-all Addresses

When the destination IP address of an incoming packet is the IP broadcast address, FTOS rewrites the
address to match the configured broadcast address.
In Figure
1. Packet 1 is dropped at ingress if no UDP helper address is configured.
| IPv4 Routing
436
20-14:
show interfaces
, as shown in